Study on Freckle of a High-Alloyed GH4065 Nickel Base Wrought Superalloy

doi:10.11900/0412.1961.2018.00218

Acta Metall Sin

2019, Vol. 55

Issue (3): 417-426 DOI: 10.11900/0412.1961.2018.00218

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Study on Freckle of a High-Alloyed GH4065 Nickel Base Wrought Superalloy

Zixing WANG^1,²,Shuo HUANG³,Beijiang ZHANG³,Lei WANG¹(

),Guangpu ZHAO³

1. Key Lab for Anisotropy and Texture of Materials, Ministry of Education, Northeastern University, Shenyang 110819, China
2. Research Institute, Baoshan Iron & Steel Co Ltd, Shanghai 201900, China
3. High Temperature Materials Research Division, Central Iron & Steel Research Institute, Beijing 100081, China

Cite this article:

Zixing WANG,Shuo HUANG,Beijiang ZHANG,Lei WANG,Guangpu ZHAO. Study on Freckle of a High-Alloyed GH4065 Nickel Base Wrought Superalloy. Acta Metall Sin, 2019, 55(3): 417-426.

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Abstract

GH4065 alloy is a new type of high-alloyed wrought superalloy, in which freckle defect is extremely prone to form in large ingot. In the present research, the freckle of GH4065 alloy bar with the diameter of 280 mm produced by vacuum induction melting (VIM)+electroslag remelting (ESR)+vacuum arc remelting (VAR) triple smelting was studied. The macrostructure, secondary phases and grain structure of the freckle were investigated, the influences of solute elements on the freckle were analyzed, and both the mechanism and control methods were also discussed. The results show that the freckle in GH4065 alloy is caused by channel segregation with the low-density Ti and Nb-rich melt flows. Additionally, lots of lath-like η-phases, block M₃B₂ borides and MC carbides are formed in the forged condition. It is confirmed by the thermodynamic calculations that the η-phases, M₃B₂ borides and MC carbides are much easier forming in the freckle than that in matrix. After heat treatment, compared with matrix, the lathy η-phases are still existed in the freckle; the size and quantity of primary γ′ phases increase significantly while the size and morphology of the secondary γ′ phase are basically identical, only with less quantity. It has been found that due to the high content of γ′ phase, the γ′ dissolution temperature in the freckle is higher than that in the matrix. This induces an impeded recrystallization process caused by the coarsened γ′ phases during forging process and the grain size of the freckle region is significantly smaller than that of matrix. Based on this study, the formation of freckle can be effectively controlled by meticulous controlling of the previous smelting process, releasing of electrode residual stress, suitably reducing VAR melting rate, and accelerating VAR cooling.

Key words: nickel-base alloy GH4065 alloy freckle density difference control method

Received: 22 May 2018

ZTFLH:

TG146.1

Fund: National Natural Science Foundation of China(U1708253)

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	Zixing WANG
	Shuo HUANG
	Beijiang ZHANG
	Lei WANG
	Guangpu ZHAO

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https://www.ams.org.cn/EN/10.11900/0412.1961.2018.00218 OR https://www.ams.org.cn/EN/Y2019/V55/I3/417

Fig.1 Freckle morphologies of the GH4065 alloy(a, b) transverse macrostructure (c) longitudinal microstructure

Table 1 EPMA quantitative analyses of GH4065 alloy freckle (mass fractoin / %)

Fig.2 Backscattered electron (BSE) image (a) and EPMA line scanning (b) of the GH4065 alloy freckle

Fig.3 BSE image and EPMA elemental mappings of the GH4065 alloy freckle

Table 2 EPMA analyses of the secondary phase in the GH4065 alloy freckle (mass fractoin / %)

Fig.4 TEM image of the carbide and boride formed in the GH4065 alloy freckle (a) and electron diffraction pattern of M₃B₂ (b)

Fig.5 SEM images of normal region (a~d) and freckles (e~h) in the forged (a, b, e, f) and heat-treated (c, d, g, h) GH4065 alloys (Insets in Fig.5d and h show the tertiary γ' morphologies)

Fig.6 EBSD grain boundary reconstruction photos of the forged (a) and heat treated (b) GH4065 alloy freckle (RX—recrystallization)

Fig.7 EBSD misorientation distributions chart of theGH4065 alloy freckle

Fig.8 EBSD results of the forged (a~c) and heat treated (d~f) GH4065 freckle showing banded profile and grain boundary reconstruction (a, d), phase distribution (b, e) and orientation (c, f) (GB—grain boundary, Co——coherency, Inco—incoherency)

Fig.9 Elemental distribution curves of the GH4065 alloy during solidification

Fig.10 Density comparison between matrix and freckle regions of the GH4065 alloy

Fig.11 Macrostructure of GH4065 alloy VAR ingot with the diameter of 508 mm (VAR—vacuum arc remelting)

Fig.12 Dendritic microstructure of GH4065 alloy ingot

Table 3 Thermodynamic statistics of the secondary phase in the GH4065 alloy during solidification process and at thermodynamic equilibrium

[1]	Tian S F, Zhang G Q, Li Z, et al. The disk superalloys and disk manufacturing technologies for advanced aero engine [J]. J. Aeron. Mater., 2003, 23(suppl.): 233
[1]	田世藩, 张国庆, 李周等. 先进航空发动机涡轮盘合金及涡轮盘制造 [J]. 航空材料学报, 2003, 23(增刊):233)
[2]	Devaux A, Georges E, Héritier P. Development of new C&W superalloys for high temperature disk applications [J]. Adv. Mater. Res., 2011, 278: 405
[3]	Jiang H F. Requirements and forecast of turbine disk materials [J]. Gas Turb. Exp. Res., 2002, 15(4): 1
[3]	江和甫. 对涡轮盘材料的需求及展望 [J]. 燃气涡轮试验与研究, 2002, 15(4): 1)
[4]	Wang X D, Wang H C. Improved development superalloys, promote the aero-engine development [A]. The Thirteenth Session of the Annual China Superalloys Conference [C]. Beijing: Metallurgical Industry Press, 2015: 3
[4]	王旭东, 王海川. 改进发展高温合金, 推动航空发动机研制 [A]. 第十三届中国高温合金年会论文集 [C]. 北京: 冶金工业出版社, 2015: 3
[5]	Williams J C, Starke E A Jr. Progress in structural materials for aerospace systems [J]. Acta Mater., 2003, 51: 5775
[6]	Zhang B J, Zhao G P, Zhang W Y, et al. Investigation of high performance disc alloy GH4065 and associated advanced processing techniques [J]. Acta Metall. Sin., 2015, 51: 1227
[6]	张北江, 赵光普, 张文云等. 高性能涡轮盘材料GH4065及其先进制备技术研究 [J]. 金属学报, 2015, 51: 1227
[7]	Du J H, Zhao G P, Deng Q, et al. Development of wrought superalloy in China [J]. J. Aeron. Mater., 2016, 36(3): 27
[7]	杜金辉, 赵光普, 邓群等. 中国变形高温合金研制进展 [J]. 航空材料学报, 2016, 36(3): 27)
[8]	Donachie M J, Donachie S J. Superalloys: A Technical Guide [M]. 2nd Ed., Materials Park, OH: ASM International, 2002: 41
[9]	Dong J X, Zhang M C, Zeng Y P. Freckle formation mechanism and its criterion [J]. Ordn. Mater. Sci. Eng., 2005, 28(1): 1
[9]	董建新, 张麦仓, 曾燕屏. "黑斑"形成机理及判据 [J]. 兵器材料科学与工程, 2005, 28(1): 1)
[10]	Zhong Z Y, Zhuang J Y. Development of several important problems on producing technologies of wrought superalloy [J]. J. Iron Steel Res., 2003, 15(7): 1
[10]	仲增墉, 庄景云. 变形高温合金生产工艺中几个重要问题的研究和进展 [J]. 钢铁研究学报, 2003, 15(7): 1)
[11]	Auburtin P, Wang T, Cockcroft S L, et al. Freckle formation and freckle criterion in superalloy castings [J]. Metall. Mater. Trans., 2000, 31B: 801
[12]	Genereux D P, Borg A C. Characterization of freckles in a high strength wrought nickel superalloy [A]. Superalloys2000 [C]. Pittsburgh: TMS, 2000: 19
[13]	Dai P C, Wei Z G, Wang Z X, et al. The microstructure analysis and formation mechanism research for freckle defect of a Ni-based superalloy [J]. Bao-Steel Technol., 2015, (5): 49
[13]	代朋超, 魏志刚, 王资兴等. 一种镍基高温合金黑斑缺陷的组织分析及形成机理研究 [J]. 宝钢技术, 2015, (5): 49)
[14]	Dong J X, Zhang M C, Zeng Y P. Microstructure behavior and freckle characteristics for GH706 superalloy [J]. Rare Met. Mater. Eng., 2006, 35: 176
[14]	董建新, 张麦仓, 曾燕屏. Inconel 706合金宏观偏析"黑斑"的形成特征及组织行为 [J]. 稀有金属材料与工程, 2006, 35: 176
[15]	Van Den Avyle J A, Brooks J A, Powell A C. Reducing defects in remelting processes for high-performance alloys [J]. JOM, 1998, 50(3): 22
[16]	Auburtin P, Cockcroft S L, Mitchell A. Liquid density inversions during the solidification of superalloys and their relationship to freckle formation in castings [A]. Superalloy1996 [C]. Pittsburgh: TMS, 1996: 443
[17]	Schneider M C, Gu J P, Beckermann C, et al. Modeling of micro- and macrosegregation and freckle formation in single-crystal nickel-base superalloy directional solidification [J]. Metall. Mater. Trans., 1997, 28A: 1517
[18]	Auburtin P, Cockcroft S L, Mitchell A, et al. Freckle formation in superalloys [A]. Superalloys2000 [C]. Pittsburgh: TMS, 2000: 255
[19]	Han Z Q, Liu B C. Numerical simulation on channel segregation in vertically unidirectional solidification process [J]. Acta Metall. Sin., 2003, 39: 140
[19]	韩志强, 柳百成. 垂直定向凝固条件下通道偏析形成过程的数值模拟 [J]. 金属学报, 2003, 39: 140
[20]	Zhang B J, Zhao G P, Zhang W Y, et al. Deformation mechanisms and microstructural evolution of γ+γ′ duplex aggregates generated during thermomechanical processing of nickel-base superalloys [A]. Superalloys 2016 [C]. Pittsburgh: TMS, 2016: 487
[21]	Wlodek S T, Kelly M, Alden D A. The structure of René 88DT [A]. Superalloys 1996 [C]. Pittsburgh: TMS, 1996: 129
[22]	Heaney J, Lasonde M, Powell A, et al. Development of a new cast and wrought alloy (René 65) for high temperature disk applications [A]. 8th International Symposium on Superalloy 718 and Derivatives [C]. Pittsburgh: TMS, 2014: 67
[23]	Schafrik R E. Materials for a non-steady-state world [J]. Metall. Mater. Trans., 2016, 47A: 2539
[24]	Crozet C, Devaux A, Forestier R, et al. Effect of ingot size on microstructure and properties of the new advanced AD730TM superalloy [A]. Superalloys 2016 [C]. Pittsburgh: TMS, 2016: 437
[25]	Moyer J M, Jackman L A, Adasczik C B, et al. Advances in triple melting [A]. Superalloys 718, 625, 706 and Various Derivatives [C]. Pittsburgh: TMS, 1994: 39

[1]	Dexin MA. FRECKLE FORMATION DURING DIRECTIONALSOLIDIFICATION OF COMPLEX CASTINGSOF SUPERALLOYS[J]. 金属学报, 2016, 52(4): 426-436.
[2]	FENG Shaobo, ZHANG Nannan, LUO Xinghong. INFLUENCE OF SEGREGATION ON LIQUID DENSITY IN THE MUSHY ZONE OF DZ483 Ni-BASED SUPERALLOY[J]. 金属学报, 2012, 48(5): 541-546.
[3]	YANG Wangyue;ZHANG Jishan;CHEN Guoliang;ZHANG Shusheng;GENG Qingquan;HUANG Linqi;HUANG Zhenxia Beijing University of Iron and Steel Technology; Fushun Steel Works; Chengdu; Xindu Engine CompanyDepartment of Materials;Beijing University of Iron and Steel Technology Beijing. EFFECT OF INTERVAL OF COMPRESSIVE OVERLOAD PEAK ON MTIGUE-CREEP INTERACTION FOR A Ni-BASE SUPERALLOY[J]. 金属学报, 1988, 24(3): 200-205.

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